Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: c69c4853e6d259a70cbadd69628a6b73f1383bc2
https://github.com/WebKit/WebKit/commit/c69c4853e6d259a70cbadd69628a6b73f1383bc2
Author: Basuke Suzuki <[email protected]>
Date: 2026-06-03 (Wed, 03 Jun 2026)
Changed paths:
M Source/WebKit/UIProcess/WebProcessPool.cpp
M Tools/TestWebKitAPI/Tests/WebKit/WKWebView/SiteIsolation.mm
Log Message:
-----------
[Site Isolation] Enable MultiProcessBackForwardCache automatically when Site
Isolation is active
https://bugs.webkit.org/show_bug.cgi?id=314699
rdar://176944362
Reviewed by Sihui Liu.
The MultiProcessBackForwardCacheEnabled preference has been off-by-default and
required to be
toggled on independently from SiteIsolationEnabled. In practice the two
features are meant to be
used together: under Site Isolation, BFCache relies on the UIProcess
coordination this flag
unlocks (BackForwardCache::addIfCacheable refuses any SI page when the flag is
off, per the guard
from bug 313657).
Flip the preference on automatically at page creation time whenever
SiteIsolationEnabled is on,
mirroring the existing pattern for UseUIProcessForBackForwardItemLoading in
WebProcessPool.
Drop the now-redundant `enableFeature(configuration,
@"MultiProcessBackForwardCacheEnabled")`
calls from the SiteIsolation.mm API tests (including
GoBackToPageWithIframeBFCache) — every
affected test goes through siteIsolatedViewAndDelegate, which sets up SI, so
the preference is
auto-enabled by the new code path.
Adjust SiteIsolation.mm tests whose pre-conditions changed because of the
auto-enable:
- DrawAfterNavigateToDomainAgain, IframeRedirectCrossSite: extend the expected
frame trees to
include the cached iframe-process tree that now stays alive through the
cross-site nav.
- NavigationWithIFrames: replace waitForDidFinishLoadInSubframe (which doesn't
fire on BFCache
restore) with a frameTreesMatch spin pattern.
- ShutDownFrameProcessesAfterNavigation, GoBackToPageWithIframe, ProcessReuse:
turn BFCache off
via the process pool config (pageCacheEnabled = NO) — the assertions in these
tests are about
pre-BFCache semantics (process teardown, reload-style goBack tree,
WebProcessCache reuse
counted via WebPages) that BFCache deliberately changes.
- siteIsolatedViewWithSharedProcess: disable BFCache on the WebProcessCache
process pool
(EnableProcessCache::Yes) for the same reason — those tests assert
process-reuse semantics that
BFCache would otherwise perturb.
- PostMessageWithMessagePorts: disable BFCache; the test exercises MessagePort
delivery across
site-isolated processes, not BFCache, and the same-site navigation must not
cache the page
holding the port.
Covered by existing SiteIsolation.MultiProcessBFCache* tests plus the adjusted
tests above.
* Source/WebKit/UIProcess/WebProcessPool.cpp:
(WebKit::WebProcessPool::createWebPage):
* Tools/TestWebKitAPI/Tests/WebKit/WKWebView/SiteIsolation.mm:
(siteIsolatedViewWithSharedProcess):
(TEST(SiteIsolation, PostMessageWithMessagePorts)):
(TEST(SiteIsolation, IframeRedirectCrossSite)):
(TEST(SiteIsolation, NavigationWithIFrames)):
(TEST(SiteIsolation, ShutDownFrameProcessesAfterNavigation)):
(TEST(SiteIsolation, DrawAfterNavigateToDomainAgain)):
(TEST(SiteIsolation, GoBackToPageWithIframe)):
(TEST(SiteIsolation, GoBackToPageWithIframeBFCache)):
(TEST(SiteIsolation, ProcessReuse)):
Canonical link: https://commits.webkit.org/314514@main
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